Molar Ratio Of Nickel Research Articles

A structurally controllable flower-shaped phosphide derived from metal-organic frameworks for high-performance supercapacitors

In this study, the flower-shaped phosphide (C/NiCoP) has been synthesized by the solvothermal method and phosphorization. The results indicate that the morphology of the samples can be modulated by varying the metal ratio of the precursor (nickel and cobalt-based metal-organic frameworks, NiCo-MOFs). The SEM and TEM analysis prove that the obtained C/NiCoP has a very complete flower-like structure, when the molar ratio of nickel and cobalt is 1: 1. The electrochemical test shows that the specific capacitance of C/NiCoP is 773 C/g at 1 A/g. The asymmetric supercapacitor (ACS) consisting of activated carbon (AC) and C/NiCoP offers a high energy density of 62.4 Wh kg−1 at a power density of 850.0 W kg−1. The exceptional electrochemical performance is attributed to this unique structure, which exposes more active sites. Additionally, many voids are generated on the surface of C/NiCoP along with the Kirkendall effect, allowing for rapid ion transmission to enhance the Faraday reaction between the electrode and the electrolyte.

The Slight Adjustment in the Weight of Sulfur Sheets to Synthesize β-NiS Nanobelts for Maintaining Detection of Lower Concentrations of Glucose through a Long-Term Storage Test.

The β-nickel sulfide (β-NiS) nanobelts were fabricated by electrodepositing a nickel nanosheet film on Indium tin oxide (ITO)-coated glass substrates and sulfuring the nickel film on ITO-coated glass substrates. The sulfurization method can be used to form nanobelts without a template. A small glass tube was used to anneal the sulfur sheet with a nickel nanosheet film. After applying vacuum to the tube, the specimen was annealed at 500 °C. By adjusting the weight of the sulfur sheet in a small glass tube, a nanobelt structure can be formed on the film for 4 h. The β-NiS nanobelt film had a sulfide and nickel molar ratio that was nearly 0.7 (S/Ni). After five years of a long-term storage test, the β-NiS nanobelt films were able to measure the glucose in a solution with the value of sensitivity of 8.67 µA cm-2 µM-1. The β-NiS nanobelt film also detected glucose with a limit of low detection (LOD) of around 0.173 µM. The estimation of reproducibility was over 98%. Therefore, the β-NiS nanobelt film has a significant ability to detect low concentrations of glucose in a solution.

Characteristics of Thin High Entropy Alloy Films Grown by Pulsed Laser Deposition

Starting from solid-solutions (SS) of AlCoCrFeNix high-entropy alloys (HEAs) that have been produced with high purity constituent elements by vacuum arc remelting (VAR) method varying the nickel molar ratio x from 0.2 to 2.0, we investigated the synthesis of protective thin films of HEAs and high-entropy nitrides (HENs) with the aid of the pulsed laser deposition (PLD) system. The structure of all ten available bulk targets have been examined by means of X-Ray Diffraction (XRD), as well as their elemental composition by means of energy dispersion X-ray spectroscopy (EDS). Three targets with nickel molar composition x = 0.4, 1.2 and 2.0 corresponding to BCC, mixed BCC and FCC, and finally FCC structures were used for thin film depositions using a KrF excimer laser. The depositions were performed in residual low vacuum (10−7 mbar) and under N2 (10−4 mbar) at room temperature (RT~25 °C) on Si and glass substrates. The deposited films’ structure was investigated using grazing incidence XRD, their surface morphology, thickness and elemental composition by scanning electron microscopy (SEM), EDS and X-ray photoelectron spectroscopy (XPS), respectively. A homemade four-point probe (4PP) set-up was applied to determine layers electrical resistance. Besides, a Nanoindentation (NI) was employed to test films’ mechanical properties. XRD results showed that all deposited films, regardless of the initial structure of targets, were a mixture of FCC and BCC structures. Additionally, the quantitative and qualitative EDS and XPS results showed that the elemental composition of films was rather close to that of the targets. The depositions under an N2 atmosphere resulted in the inclusion of several percentage nitrogen atoms in a metallic nitride type compound into films, which may explain their higher electrical resistivity. The Young’s modulus, nanohardness and friction coefficient values showed that the deposited films present good mechanical properties and could be used as protective coatings to prevent damage in harsh environments.

Nickel-doped cobalt molybdate nanorods with excellent cycle stability for aqueous asymmetric supercapacitor

Herein, nickel-doped cobalt molybdate (NixCo1-xMoO4, x = 0, 0.1, 0.3, 0.4, 0.5, 0.6) with nanorods structure are successfully prepared through a facile co-precipitation approach. The molar ratio of nickel and cobalt would affect the morphologies. The Ni0.5Co0.5MoO4 electrode exhibits satisfactory specific capacity and rate performance (325.9 C/g at 0.5 A/g, 260 C/g at 10 A/g). Moreover, the asymmetric supercapacitor (ASC) device is assembled using Ni0.5Co0.5MoO4 and carbon spheres as positive and negative electrodes, respectively. The ASC device possesses high energy density of 31.57 Wh/kg at the power density of 400 W/kg, and even maintains high energy density of 13.56 Wh/kg at the power density of 8000 W/kg. Meantime, the ASC device possesses excellent capacitance retention rate and coulomb efficiency after 5000 charge-discharge cycles. And a red light-emitted diode is illumed using two ASC devices in series.

Facile Preparation of Ni-Co Bimetallic Oxide/Activated Carbon Composites Using the Plasma in Liquid Process for Supercapacitor Electrode Applications.

In this study, a plasma in a liquid process (PiLP) was used to facilely precipitate bimetallic nanoparticles composed of Ni and Co elements on the surface of activated carbon. The physicochemical and electrochemical properties of the fabricated composites were evaluated to examine the potential of supercapacitors as electrode materials. Nickel and cobalt ions in the aqueous reactant solution were uniformly precipitated on the AC surface as spherical nanoparticles with a size of about 100 nm by PiLP reaction. The composition of nanoparticles was determined by the molar ratio of nickel and cobalt precursors and precipitated in the form of bimetallic oxide. The electrical conductivity and specific capacitance were increased by Ni-Co bimetallic oxide nanoparticles precipitated on the AC surface. In addition, the electrochemical performance was improved by stable cycling stability and resistance reduction and showed the best performance when the molar ratios of Ni and Co precursors were the same.

Nanostructured nickel phosphide as an efficient photocatalyst: Effect of phase on physical properties and dye degradation

Nickel phosphide nanostructures are synthesized by hydrothermal method. The effect of different nickel phosphide phases on structural, morphological, and optical properties as well as photocatalytic performance are investigated. XRD results show that initially, the Ni12P5 phase is formed, then by increasing the P/Ni molar ratio in the starting solution, product phase gradually transforms to the Ni2P phase. The results showed that crystalline phase and morphology of the nanostructures affects the catalytic performance of the samples. The best result for methylene blue dye removal was achieved for the sample with 35/1 phosphorus to nickel molar ratio which had pure Ni2P phase.

Remarkable impact of Ni2+ ion on the structural, optical, and magnetic properties of hexagonal wurtzite ZnS nanopowders

Ni-substituted zinc sulfide Zn1−xNixS (x = 0.0–0.8) nanopowders have been purposefully assembled using hydrothermal strategy based on inexpensive chloride salts and thiourea as sulfur sources. By X-ray diffraction, a hexagonal wurtzite structure with preferential orientation along the (0 0 8) plane was recognized at hydrothermal temperature 150 °C for period 24 h with nickel ion content. However, binary ZnS/Ni3S4 nanocomposites were identified by enhancing the nickel molar ratio up to 0.2–0.3 (20–30%). Whereas, ternary ZnS/Ni3S4/NiS nanocomposites were accomplished by increasing Ni ion molar ratio in the range from 0.4 to 0.8. The microstructure of the Ni replaced ZnS particles from 0.0 to 0.6 exhibited microspheres like structure and with increasing the Ni2+ ion concentration, the microspheres converted to three-dimensional layers. The optical band-gap energy was slightly reduced from 3.39 to 3.32 eV with increasing the Ni ion addition from 0.1 to 0.3. Otherwise, two band-gap energies were existed to be 3.16–1.60 and 2.95–1.45 eV at Ni2+ ion substitution 0.60 and 0.80 molar ratios, respectively. Photoluminescence spectra measurements indicated that pure and Ni ion-substituted ZnS (0.1 and 0.2 molar ratios) were manifested three emission bands in the ranges of strong UV emission peak 350–375 nm with the weakest blue UV emission band 375–387 nm and the broadband visible emission at 400–600 nm. Eventually, weak ferromagnetic behavior was evidenced for different Ni2+-substituted ZnS. The saturation magnetization was found to be maximum value of Ms of 0.33 emu/g as the result of improving the crystallization of cubic polydymite Ni3S4 structure at nickel ratio of 0.3.

Preparation of Nickel and Manganese Dioxide by Co-Precipitation and its Electrochemical Capacitive Properties

The precursor nickel and manganese carbonates were synthesized by co-precipitation with sodium carbonate as precipitant, and then nickel and manganese oxides were gained after calcination. The phase and morphology of the synthesized product were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), and the electrochemical characterization was performed using cyclic voltammetry (CV), galvanostatic charge–discharge tests (GCD) and electrochemical impedance spectroscopy (EIS) in a 6mol/L KOH aqueous solution electrolyte. The result showed that the products were the mixture of nickel and manganese oxides and solid solution. nanoparticles and spherical particles were gained by controlling the molar ratio of nickel and manganese. All of the samples exhibited typical Faradic redox capacitance. The specific capacitance was different with the change of nickel and manganese molar ratio. The specific capacitance (Cs) reached 130F/g at 1A/g when the ratio was 2:1.

Novel synthesis of high surface area SiC by carbothermal reduction process

SiC nanoparticles and nanofibres were synthesised by simple carbothermal reduction technology. Low cost water glass and phenolic resin were used as raw materials, and nickel nitrate was added as catalyst. The synthesised samples were characterised by X-ray diffraction, field emission scanning electron microscope, TEM, N2 adsorption–desorption isotherms and fluorescence spectrophotometer. The results indicate that nickel catalyst can change the morphology and the surface area of SiC. When molar ratio of nickel to silicon equals to 0·0141, SiC nanoparticles with an average diameter of 40 nm are synthesised, and the surface area reaches maximum value, 81 m2 g−1. However, SiC nanofibres are prepared with the increase in nickel content, but the surface area decreases. The synthesised SiC have stable and strong photoluminescence property. The synthetic technique has the advantage of being simple, efficient and economical.

Effect of O2/Ni ratio on structure and surface morphology of atmospheric pressure MOCVD grown NiO thin films

ABSTRACTEffect of oxygen to nickel molar ratio (O2/Ni) on the crystallinity of atmospheric pressure metal organic chemical vapor deposition (APMOCVD) grown NiO at 500°C is reported. X-ray diffraction (XRD) analysis including grazing incident angle θ of 0.6°, θ-2θ, ɸ and rocking curve scan are employed for crystallographic characterization. Furthermore, surface roughness is studied by atomic force microscopy (AFM). No evidence of diffraction peaks in X-ray grazing incident angle measurement confirms that all the grown NiO films are well oriented along a certain direction. θ-2θ scan results further indicate that the samples are highly oriented only along [111] direction on (0001) sapphire substrates. The analysis of full width at half maximum (FWHM) of rocking curve scan of (111) plane shows that higher O2/Ni ratio results in better crystallinity. The best crystallinity is achieved with FWHM as low as 0.106° at (111) rocking curve scan corresponding to 82.57nm grain size. AFM measurement shows that NiO films grown with higher O2/Ni ratio have smoother surface morphology.

Composition and phase control of Ni/NiO nanoparticles for photocatalytic degradation of EDTA

A sol–gel process followed by a calcination treatment was employed to synthesize magnetic Ni/NiO nanoparticles. The as-formed particles were characterized using XRD, TEM, UV–vis, surface area and VSM. The XRD results show that the patterns of the product synthesized using 1:1, 1:2, and 1:3 molar ratio of nickel nitrate/citric acid composed of a mixture of NiO and Ni, whereas the patterns recorded for 2:1 and 3:1 molar ratio exhibited a single NiO phase. All the prepared samples are in the form of nanoparticles with sizes locate in the range of 33 up to 118 nm for the samples prepared by different molar ratios. The photocatalytic tests were conducted for degradation of EDTA. The results show that the EDTA removal efficiency is 99.9% at 3 × 10 −3 M EDTA concentration. The reaction of Ni/NiO with EDTA follows first order kinetics with respect to EDTA. The rate constants and t 1/2 for Ni/NiO at 0.4 g/l catalyst/EDTA solution ratio were, respectively 460 min −1, 15.1 min.

ＦｅＯｘ‐ＳｉＯ２基スラグと各種のＣｕ２Ｓ‐Ｎｉ３Ｓ２‐ＦｅＳ系マット間の１，５７３Ｋにおける相平衡について

As a fundamental study for systematic and comprehensive understanding of copper and nickel smelting processes from a standpoint of thermodynamics, the phase equilibrium between the FeOX-SiO2 base slag, which was saturated with silica and containing about 6 mass % MgO, and the Cu2S-Ni3S2-FeS matte with NNi /(NNi + NCu) molar ratios of 0, 0.25, 0.5, 0.75 and 1 was investigated at 1,573 K under the partial pressure of SO2 with 0.1 atm. The slag and the matte were equilibrated in a MgO crucible and the partial pressures of oxygen and sulfur were controlled by using an Ar-SO2-S2 gas mixture passing through a sulfur reservoir. It was clarified that the partial pressures of oxygen and sulfur in relation to the iron content in the matte were almost independent of the matte species. This was considered to be ascribed to the activity of FeS in the matte which was almost constant against the matte species when the composition of iron in the matte was specified. The content of copper in the slag at a specified composition of iron in the matte decreased with increasing the nickel molar ratio, NNi /(NNi + NCu), in the matte while that of nickel increased with increasing the nickel molar ratio. It was found that the distribution ratio of silver between the slag and matte phases was considerably small at less than 0.1 and had a tendency to increase with increasing the nickel molar ratio in the matte when the composition of iron in the matte was specified. On the other hand, the distribution ratio of cobalt presented considerably large values of about 1 in the range of low iron content in the matte.

Magnetic properties of N,N′-diglycylethylenediamine chelates of nickel(II)

Magnetic susceptibilities of aqueous solutions containing a 1:1 molar ratio of nickel(II) to diglycyclethylenediaminedihydrochloride, H 2L 2+, were measured as a function of “ a” (moles of added base per mole of metal ion). A plot of molar magnetic susceptibilities as a function of “ a” indicates stoichiometric conversion of paramagnetic NiL 2+ to diamagnetic NiH −2L without the formation of paramagnetic intermediates.